Such an overview is provided in Exhibit 1. The point of this diagram is to illustrate the relationships among such items as hazardous wastes, municipal and industrial wastewaters, and non-hazardous solid wastes. It will be increasingly important to understand "where things go" as we deal with hazardous and solid waste, and wastewaters.

It is also important to note that the overview in Exhibit 1 does not deal with every source or possible exposure route of hazardous wastes or toxic substances. For example, hazardous air emissions, pesticide applications, and many "non-point" waste sources are not included in Exhibit 1. These sources and others such as wastes discharged to surface waters through a National Pollutant Discharge Elimination System (NPDES) permit are not discussed in detail in this report.

Now, let's return to RCRA and Superfund hazardous wastes, which are highlighted in the bold portion of Exhibit 1. The hazardous wastes managed under RCRA totaled about 275 million metric tons (MMT) in 1985. The overwhelming majority of this, well over 99 percent, was managed by "large quantity generators" (over 1,000 kilograms per month). A number of factors could affect the volumes of wastes generated in the future. Factors such as economic and population growth, regulatory decisions, and waste minimization efforts will influence the amount of waste produced. As industrial production increases the volume of industrial wastes produced could also increase. However, efforts to recycle and reuse wastes, as well as programs to minimize the amount of waste generated are likely to temper increases in waste volumes.

TREATMENT AND DISPOSAL

Referring again to the bold print portion of Exhibit 1, let's now outline the treatment and disposal part of the hazardous waste system.

First, it is important to note that about 96 percent of all RCRA hazardous waste is managed on the sites of private companies, the remaining 4 percent goes to off-site commercial treatment and disposal facilities. An approximate breakdown of the treatment and disposal system follows.

Source: National Screening Survey, U.S. EPA, Office of Solid Waste (1986). • Breakdown of on-site versus off-site waste volumes is not currently available. ** Total exceeds 275 MMT as deep-well injection, which is covered under the Safe Drinking Water Act, is included. MMT-million metric wet tons per year

The above table relates to about 3,000 facilities which treat, store, or dispose of RCRA hazardous waste. There are currently over 175 on-site incinerators and 14 commercial incinerators. A list of commercial incinerators is contained in Appendix A of this report. In addition to incineration, there are many other treatment practices including biological wastewater treatment, solidification, steam stripping, and treatment impoundments. Most current treatment systems consist of on-site impoundments handling relatively dilute wastewaters. There are about 430 operating land disposal facilities, approximately 60 of which are commercial facilities which accept a wide range of wastes. Appendix B of this report contains a list of commercial operating land disposal facilities. Finally, while the majority of deep-well injection systems are located on-site, a few commercial facilities also use deep-well injection systems. These facilities are identified in Appendix C of this report.

REGULATORY AND OTHER EFFECTS

Due to a large number of new statutory and other requirements, hazardous waste management must deal with a series of "moving targets". Some of the more significant ones are briefly outlined below.

Land Disposal Restrictions and Technology Standards

The Hazardous and Solid Waste Amendments of 1984 (HSWA) required that EPA ban the land disposal of over 400 chemicals and waste streams unless the wastes are treated, or it can be demonstrated that there will be "no migration as long as the waste remains hazardous." The solvents and dioxin portion of the rules went into effect in November 1986. Others will be promulgated over the next 2 to 3 years. The major impact of these rules will be to significantly increase treatment required for many hazardous wastes.